1. Field of the Invention
This invention relates generally to a semiconductor device, and, more particularly, to a programmable capacitor associated with an input/output pad in the semiconductor device.
2. Description of the Related Art
Traditional semiconductor devices are formed in a die that includes hundreds or thousands of individual semiconductor components such as transistors, memory elements, and the like. The die is generally formed of multiple layers of semiconductor material, such as silicon dioxide, and the various components are formed in the semiconductor layers and linked by electrically conducting lines or vias. For example, a transistor may be formed in the semiconductor material by well-known processes including etching, deposition, implantation, thermal growing, and the like.
The die also includes one or more bond pads formed around the perimeter of an upper surface of the die. The bond pads are used to couple the semiconductor device to external electrical circuits. By linking the bond pads to the other components on the die by electrically conducting lines or vias, signals may be transmitted between the external electrical circuits and the components on the die. For example, the bond pads may be coupled to input/output (I/O) driver circuits formed in the die, and the I/O driver circuits may provide various signals to electrical circuits coupled to the bond pads.
Portions of the die near the bond pad may be subject to a variety of stresses, including mechanical stresses, thermal stresses and the like, when the bond pads are formed. These stresses may damage active circuitry and metal components that are near the bond pad. Consequently, typical bond pad design rules dedicate a selected volume of the die to the bond pad. According to these rules, no metal or active components unrelated to the bond pad may be formed in the bond pad volume. Although the size of typical semiconductor components has steadily decreased, and the density of components that may be formed on the die has increased, the selected bond pad volume has remained nearly constant. Thus, the bond pad volume now occupies a larger portion of the die, both in real and relative terms, causing a reduction in the volume of the die that is available for active circuitry and metal components.